The whale stopped clicking about 5 min into the playback, approximately 1 min after the received level of the killer whale sound reached 98 dB re 1 μPa SPL (fig. 10, Tyack et al. 2011). The whale then again made a slow ascent, the slowest analyzed from a set of 32 deep foraging dives from six whales tagged at this site (Tyack et al. 2011). After surfacing, the whale swam away from the playback location for approximately 10 h, before the tag detached and was then recovered at 24.8136ºN, 77.6265ºW, a location approximately 24 km away from the deployment

site (Fig. 1). Utilizing speed learn more estimation from the pitch angle and the rate of change of depth recorded on the Dtag, a rough approximation of the tagged whale’s path, called a pseudo-track, was generated (Tyack et al. 2011) (Fig. 2). As seen in Fig. 2, after cessation of the MFA sonar playback, the whale briefly maintained a course heading to the north. After several hours, the whale started a deep foraging dive. After cessation of the killer whale playback, the whale maintained a heading directed to the north for the remainder of the tag attachment (Fig. 3). If the see more whale continued on this course after tag detachment, it would have passed through the only deep-water exit from the TOTO canyon. In order to test whether the whale altered its movement patterns in response to either the

MFA sonar or killer whale playback, we performed a rotation test of the heading data from the Dtag. We used a nonparametric likelihood ratio test (NLR) (Cao and Van Keilegom 2006) to determine if the distribution of Δheading was different in the two periods: before and after cessation of the MFA and killer whale playbacks. medchemexpress The kernel density estimate (KDE) was calculated for each of the time periods (Fig. 4) and we assessed the significance of the observed

value of the NLR statistic via a discrete-time version of a rotation test (Deruiter and Solow 2008). Of 312 NLR values generated using the breakpoint defined by cessation of the MFA playback, 146 exceeded the observed value, giving a P-value of 0.468 (Fig. S2). This indicates that there is no significant change in the whale’s movements after the cessation of the MFA sonar playback. Of 312 values of the NLR statistic generated in this way for the killer whale playback, none exceeded the observed value (Fig. 5) giving an estimated P-value of <0.005. Therefore, we conclude that there is a significant difference in the whale’s movement behavior between these two periods, as reflected in the distribution of Δheading. In order to further our understanding of how the beaked whale responded to the killer whale playback, we tested for a difference in the dispersion of Δheading after the killer whale breakpoint, as measured by the angular standard deviation (Fisher 1995). As before, significance was assessed by rotating the order of the time series of Δheading. Of the 312 values generated this way, two exceeded the observed value, giving an estimated P = 0.